Since a polymer-type fuel cell using a solid polymer electrolyte such as a polymer electrolyte has a high energy conversion efficiency, and is a thin and small type, and is light, it has been actively developed for a home cogeneration system and a motorcar. As a structure of the prior art of such the fuel cell, a structure shown in FIG. 16 is known (e.g. see Nikkei Mechanical supplement volume “Frontier of Fuel Cell Development” published on Jun. 29, in 2001, published by Nikkei BP, Chapter 3 PEFC, 3.1 Principles and Characteristics, p 46).
That is, as shown in FIG. 16, an anode 101 and a cathode 102 are disposed with holding a solid polymer electrolyte membrane 100. Further, a unit cell 105 is constructed by holding by one pair of separators 104 via a gasket 103. In each of separators 104, a gas flow path groove is formed and, by contact with an anode 101, a flow path for a reducing gas (e.g. hydrogen gas) is formed and, by contact with a cathode 102, a flow path for an oxidizing gas (e.g. oxygen gas) is formed. Each gas is supplied for an electrode reaction (chemical reaction at electrode) by the action of a catalyst carried in the interior of an anode 101 or a cathode 102 while passing through each flow path in a unit cell 105, and generation of an electric current and ionic conduction are made.
A fuel cell N is constructed by stacking a number of the unit cells 105, and electrically connecting unit cells 105 in series, and an electrode 106 can be taken out through stacked unit cells 105 on both ends. Such the fuel cell N is paid an attention in various utilities, particularly, as an electric motorcar supply or a distributed supply for household use, because of characteristics being clean and highly effective.
On the other hand, with activation of IT techniques in recent years, there is a tendency that mobile instruments such as a mobile phone, a notebook computer, and a digital camera are frequently used and, as an electric supply for them, a lithium ion secondary cell is used in most cases. However, with high functionalization of mobile instruments, a consumed power is gradually increased and, as an electric supply therefor, attention has focused on a fuel cell which is clean and highly effective.
However, in the prior structure as shown in FIG. 16, since a structure has no degree of freedom, it is difficult to realize a thinner, small and lighter type required as an electric supply for mobile instruments, and to make a high degree of freedom for a shape, and there is a problem of deteriorated maintenance. Further, it is difficult to supply respectively an oxidizing gas and a reducing gas in a fuel cell without mixing them, and to make a sealed structure, and it is difficult to reduce a size and a weight of a fuel cell while satisfying these conditions. In other words, conventionally, as cell parts have been interconnected with a securing part such as a bolt and a nut to apply a certain pressure to cell parts, it is necessary to enhance rigidity of each part in order to secure the sealing property, and thinning, miniaturization, weight reduction, and free shape design have been unavoidably difficult.
Meanwhile, the following Japanese Unexamined Patent Publication No. 58-176881 discloses a flat-type liquid fuel cell comprising a unit cell in which a liquid fuel is stored. The fuel cell has a structure in which a circumference of a laminate of a fuel electrode, an electrolyte, and an oxidizing agent electrode is integrated with a sealing material, and this is housed in a cell casing.
However, in the aforementioned cell structure, a force for pressing a sealing material to a side wall of a laminate containing an electrode cannot be sufficiently enhanced. Therefore, for example, when a hydrogen gas fuel is pressurized to flow on a fuel electrode side, a hydrogen gas is leaked to an oxidizing agent electrode side, and there is a problem that such as reduction in an electric generating efficiency and risk of hydrogen combustion. That is, an electrode of a fuel cell has generally a porous structure and, for this reason, the aforementioned cell structure is a structure in which a pressurized hydrogen gas passes through the interior of a fuel electrode, and is easily leaked to an oxidizing agent electrode side from between a side wall of an electrolyte and a sealing material.